The casing-up of a movement, that is to say securing the movement in the case of a watch, is generally accomplished by means of braces screwed to the movement, which braces are inserted into a groove provided on the inner periphery of the case, or with the help of a casing-up ring.
It is proposed in European patent application EP 1 970 779 to undertake the casing-up by utilizing two superimposed casing-up rings, between which the movement is retained. These rings are themselves compressed between a part of the middle of the watch and the bottom of the said watch. One of the rings is provided with an opening to permit the passage of a winding stem. An annular joint is provided for the axial and radial retention of this second ring and, consequently, the movement.
Various tests, including those undertaken by the applicant, have revealed that these casing-up solutions not only transmit a shock from the case to the movement, but also amplify it. Accordingly, a cased-up movement in a watch which experiences a shock of 10,000 g will be subjected to a shock of 25,000 g, that is to say amplified by a factor of 2.5.
One solution could involve inserting a shock absorber, such as an elastomer ring, between the case and the movement, although this will require the availability of a large volume inside the case.